Following a routine sample being taken from Tolsta Village Service Reservoir which serves 218 properties in the Tolsta area of Lewis, testing has identified the presence of E.coli in this localised section of the network.
After discussions with NHS Western Isles, a Boil Notice has been put in place on the 218 properties affected.
This advises that customers should boil their water before drinking or cooking until further notice. The water is safe to use once it has been boiled.
Bottled water will also be provided to affected customers as a further measure until they receive a letter to say the notice has been lifted.
Investigations show that the potable water coming from the treatment works and to the other parts of the network is fine and that this is a localised failure associated with this tank.
However authorities are taking a precautionary approach to the customers being supplied from it.
Investigations into the cause of this failure, Tolsta Service Reservoir is ongoing with further sampling and laboratory analysis.
Further updates will be given as soon as information becomes available.